Physics at Clifton College upgrade their demonstration equipment to include the Lascells Space Tube: a quick-prep, easy to use unit that impressively demonstrates that sound waves need a medium to travel through, and cannot propagate through a vacuum.
“The Lascells Space Tube was recommended to us by my ex-boss David Richardson, who now works at the University of Bristol teaching PGCE Physics. David said this model works so much better than what we already had, which was the traditional Bell in a Bell Jar apparatus. Even with a grease seal under the bell jar and the valve closed, the vacuum pump needed to be on until just before use, as it struggled to hold the full vacuum for any length of time. It was also quite awkward for the teacher to allow air back in for the students to hear the increase in noise level (no one can hear a change whilst increasing the vacuum, the pump whirring away is far too noisy) either pulling the tube off the valve then opening this else releasing the pump’s safety valve, both of which needing quite strong fingers.
The lack of a good seal also meant that the chamber had to be evacuated in-situ, requiring lugging around the vacuum pump and the bell jar to the required classroom. With the Lascells Space Tube, the rubber o-rings make a really secure seal, so I can quickly pull a vacuum in my prep room (~30 seconds), then hand the teacher the evacuated unit to be used in lesson whenever they choose. Under the highest vacuum we can achieve, the buzzer is barely audible, as expected and can quietly sit there until needed, unheard by the students. The teacher gives an explanation, then lets the air back in by slowly opening the valve, and hey presto – you can hear the buzzer volume clearly increasing as they do so.
The suspension of the buzzer by rubber band is also very cleverly designed – this means that the buzzer is vibrationally isolated from the rest of the unit. With our older apparatus, the bell was suspended from the jar with wires, so vibrations could travel through them, causing the jar to vibrate and make noise. When air was let back into the chamber, the change in volume level wasn’t that different for students to clearly appreciate the difference between air and little air – had almost to be talked into belief by the teacher! This is not a problem with the new unit, and we are very happy with it. The equipment clearly reinforces the theory, enhancing our teaching by delivering on intended learning outcomes to the benefit of all, students, teacher and (most importantly!) technician.
With some school science equipment out there, you don’t expect a lot from it due to the quality and price. Lascells however, is a brand we have gotten to know well and the Space Tube is a prime example of how their equipment surpasses our expectations. With a limited budget, it’s really important that our money is well spent on equipment that is reliable and does what it’s meant to, and Lascells always delivers.”
– Simon Buck, Physics Technician, Clifton College
See the Lascells Space Tube product page, and find your stockist here.